In the above-described technical field, patent literature 1 discloses a technique of determining a bone cutting position from an inverted image of an unaffected bone and an image of a target bone. Patent literature 2 discloses a technique of generating a prosthetic artificial bone model based on a determined bone cutting position. Non-patent literature 1 shows software that generates 3D bone surface model (STL: Stereo Lithography) data from DICOM (Digital Imaging and Communication in Medicine) data that is a standard format of a medical image of CT (Computed Tomography)/MRI (Magnetic Resonance Imaging) or the like. Non-patent literature 2 shows software that simulates bone and joint surgery in advance using 3D bone surface model (STL) data.